Perforating typically involves the use of shaped charges in a perforating gun to form perforations or openings through casing in a well. Detonation of the shaped charges is initiated by a device known as a firing head. The firing head may be operated mechanically, electrically, by application of pressure, or via various forms of telemetry. These perforations or openings that are formed are provided such that oil or gas can flow into production tubing.
A significant concern within the industry relates to the prevention of unintended detonation of a perforating device, and particularly any detonation at the surface level. The force or energy associated with such a detonation of a perforating device is significant and one which could cause serious injury to not only an operator or handler of the specific device but also anyone or any surrounding property within a general radius of the detonation.
Existing safety devices commonly rely upon temperature and/or pressure. The perforating devices using these safety devices are not armed until the device is exposed to sufficient temperature and/or pressure, which is often those temperatures or pressures experienced in a downhole environment. With the increased frequency of the operation of deviated, highly deviated, or horizontal wells, other perforating safety systems are desired. In some such wells, for example, the necessary temperature conditions and/or pressure conditions may not be experienced within a deviated or horizontal section of the wellbore. Therefore, assemblies and systems are desirable that can provide alternative perforating safety systems for use in a deviated, highly deviated, or horizontal well, which can be independent of temperature and/or pressure conditions and can provide effective protection from unintended detonations, particularly at the surface level or in a vertical section of a well.